Channel up-mixing / down-mixing, how to compute num channels of connection?

Hi!

Reading the chapter "9 - channel up-mixing / down-mixing", from what I
understand the number of channels should be computed for each input.
However it says :

> “max”: computedNumberOfChannels is computed as *[the maximum of the
number of channels of all connections]*.

So how I understand it is that you actually need the number of channels of
each output for computing "computedNumberOfChannels". But I couldn't quite
figure out how to compute the number of channels of an ouput. Is the node's
raw channelCount?

Or did I get it all wrong?

Sebastien Piquemal

PS : for info, I am in the process of implementing the Web Audio API spec
for Node.js (https://github.com/sebpiq/node-web-audio-api).